How should I relate a recording of a song that is used as the background song for a recording that features the speech as the main focus. Is using the samples relationship sufficient?
I had a similar situation, where a particular song was performed during a longer spoken word recording. I believe the answer was just use “recording of”. Here’s an example: https://musicbrainz.org/recording/7be298c3-0ae5-4120-a7d3-300c8147e878
Well, it occurs to me belatedly that if it was an existing recording played behind new content, that might be different. In my case, the whole thing was a new recording.